One does not usually think
of pruning in connection with house plants, but there are some cases
when it becomes eminently desirable. The principles are the same
as for ordinary outdoor pruning. The cut should be made just above
the leaf which has in its axil a bud pointed in the direction you
want the plant to develop.

Pruning can be done to advantage in
September when the plants are dug up from their outdoor stations
preparatory to spending the winter indoors. Abutilon hybridum (Flowering
Maple) and Hibiscus rosa-sinensis (China Rose) can be pruned by
cutting back the shoots of the current season about one half, or
they can be pruned to advantage after repotting them in late winter
(see Fuchsia).

Chrysanthemum hortorum (Garden Chrysanthemum).
Pinch out the tips of shoots whenever they attain a length of 6 inches,
until mid-July. When 1-, 2-, or 3-stem plants are desired, they are disbranched
as soon as the required number of main shoots has been produced by removing
all side shoots when they are large enough to handle. Larger flowers are
produced by disbudding, removing all but the strongest buds from each
shoot.

Citrus Limonia (Ponderosa Lemon),
C. paradisi (Grapefruit), C. sinensis (Sweet Orange), C. taitensis (Otaheite
Orange). The only Citruses commonly offered by dealers in house plants
are Ponderosa Lemon and Otaheite Orange. The Grapefruit and Sweet Orange
usually are started from seeds for house plants. Pruning consists of the
removal of weak, twiggy growth.

Coleus (Painted Nettle)
can be grown either as a single-stemmed plant or a branching one. Your
own preference will decide which. If you plump for the first-named method,
it will require taking out axillary shoots, as in the case of Saintpaulia;
otherwise just let nature take its course, with occasional help from you
in the matter of pinching out shoot tips to prevent blossoming whenever
necessary. The flowers of Coleus are not attractive except for a few species
such as C. thyrsoideus.

Euphorbia pulcherrima (Poinsettia).
The old plants should be cut back to within about 6 inches of the pot
in April or May, repotted, and put outdoors for the summer. Cuttings may
be taken from the cut-back plants during July and early August. This last
method is preferable because it results in plants of moderate size. No
further pruning is necessary.

Fuchsia. Resting plants
should be brought into light and warmth about the end of January. When
the buds start growing, repot the plants and cut back to the strongest
shoots. If a bushy plant is required, the tips of the new shoots should
be pinched out when they have made six or eight pairs of leaves.

Gardenia. If the plant is
getting too large, prune it back one third before you set it outdoors
in the spring. When the new shoots are about 6 inches long, pinch off
the tips to promote branching. Do not pinch them after July.

Hedera helix. Although English
Ivy, Hedera helix, can be used as a house plant, it is better to choose
one of the "self-branching" mutations, such as Pittsburgh, Hahn's
Self-branching, Manda's Crested, Pittsburgh Variegated, or Shamrock.

Pruning can be done by pinching out the tips
of the shoots to make the plants more compact. There is a non-climbing
variety, H. h. erecta, which tends toward a sprawling habit. It may require
removal of some of the sprawly parts if you wish a compact plant. Rarely,
it may be possible to obtain small plants of the arborescent form of English
Ivy. The pruning of this requires the removal of the flowering panicles
and any shoots which have reverted to the juvenile climbing habit.

Nephthytis Scindapsus aureus (Ivy
Arum), S. pictus argyraeus, Philodendron cordatum (Heart-leaf
Philodendron), and similar climbing Aroids should be pruned by pinching
out the tips of the shoots as soon as they are about 8 inches long. If
you have large plants growing on a support, such as a tree-fern trunk,
a slab with bark on it, or a stout stick with moss wired on it, wait until
they reach the top of the support.

When other trailing plants such as Cissus antarctica
(Kangaroo Vine), C. rhombifolia (Grape Ivy), Ipomoea batatas (Sweet Potato),
and Boussingaultia baselloides (Madeira Vine) have reached the limits
of their supports, the tips of the shoots should be pinched out to stimulate
the growth of buds which otherwise would stay dormant.

Pelargonium domesticum (Lady Washington
Geranium). Shorten strong shoots in August or September and remove
all weak ones. P. hortorum (House, Fish, or Zonal Geranium), when dug
up in the fall, should have the top growth cut back at least one half.
If they show any tendency to make lanky shoots, pinch off the tips and
give them more light.

Rhododendron indicum (Greenhouse
Azalea) may be pruned immediately after flowering, but do not
cut them back any more than is absolutely necessary to make a shapely
bush. During the summer pinch out the tips of shoots which are outstripping
their neighbours.

Saintpaulia ionantha (African Violet).
The chief pruning to be done on African Violets is that which is necessary
to maintain a single-crown plant. It is best accomplished by removing
the side shoots when they are barely visible, pushing them out with the
aid of a pointed stick or pencil. Other pruning that may be considered
desirable is the occasional removal of a wayward leaf.

Tibouchina semidecandra (Princess
Tree, Glory Bush, or Spider Flower), a plant of many aliases,
which has been called by botanists Pleroma tibouchina, P. macranthum,
P. splendens, and also Lasiandra semidecandra, has the good trait of blooming
while it is still young. This can be pruned by cutting off the terminal
shoots when the flowers have faded.

Hoya carnosa (Wax Plant)
needs but little pruning. Merely pinch out the tips of young shoots which
are exceeding their bounds. Do not cut off the spurs (stubby growths)
from which the flowers are produced.